THE CARBOXYL-TERMINAL DOMAIN OF INSULIN-LIKE GROWTH-FACTOR-I RECEPTORINTERACTS WITH THE INSULIN-RECEPTOR AND ACTIVATES ITS PROTEIN-TYROSINE KINASE

Receptors for insulin and insulin-like growth factor-I (IR and IGFIR) consisting of the alpha(2) beta(2) structure are protein tyrosine kina ses (PTKs), Carboxyl-terminal (CT) domains of their beta subunits are structurally diverse while the PTK domains share the highest homology. , Interactions between CT and PTK domains of IR and IGFIR were studied by means of PTK activity, fluorescence energy transfer or surface pla smon resonance using BIAcore. We present evidence that IGFIR CT direct ly interacts with both IGFIR and IR, Although binding to both receptor s, stimulation of PTK activity only occurs with IR but not IGFIR, (C) 1998 Federation of European Biochemical Societies.